It's the day where all the weebs, otaku's and weeaboos can rise out of their slumber and celebrate. their weeb being.
You can just watch anime whole day and nobody will blame you for not doing anything whole day because it's anime day.
Mom: Stop watching those silly Chinese cartoons of you and do you're homework!
you: I have all the rights to watch anime, Since it is 15 april national anime day.
